The present invention relates generally to spinning devices and more particularly relates to open-end spinning devices.
A known spinning rotor such as is disclosed in German Patent Application No. 2328715 which has been laid open for public inspection on 1975-1-9, of Wilhelm Stahleiker GmbH, Reichenbach, Germany, rotates in a housing under a reduced pressure. A rear wall of the housing is provided with a bore through which a shaft of the rotor passes with the shaft being mounted outside the rear wall. The rotating parts are constructed in the form of air-conducting or air-conveying devices which act from the inside of the housing outwardly. A plurality of bores are provided in the bottom of the spinning compartment which lead to the back of the spinning rotor and terminate in the region of a sealing gap between a flange of the spinning rotor and the rear wall of the housing. The purpose of this arrangement is to produce a reduced pressure in the spinning compartment and at the same time to cool a bearing of the device.
The effectiveness of this device depends on the nature, number and arrangement of the bores in the bottom of the spinning compartment. For adequate cooling, a large number of bores must be provided which should be arranged at as large an angle as possible with respect to the axis of rotation. The provision of the bores involves considerable expense because the spinning rotors must necessarily be precisely manufactured since even small deviations in mass lead to great unbalance when the peripheral speeds of the rotor exceed 40,000 revolutions per minute. Extremely high speeds of rotation cannot be achieved with rotors which are out-of-balance because the detrimental effect of the unbalance increases quadratically with increasing speed. In addition, a relatively large spinning-compartment housing has an unfavorable effect both on the energy consumption and on the development of noise because of the large amounts of air which are made turbulent and are heated by the high speed spinning rotor. Additional energy then has to be expended to draw off this heat.
Accordingly, an object of the present invention is to provide an open-end spinning device having both a reduced energy consumption and a lowered noise level and wherein no expensive machining of the spinning rotor is necessary for the independent production of reduced pressure.
In the open-end spinning device of the present invention, a spinning rotor is provided in a spinning-compartment housing with internal contours of the spinning-compartment housing corresponding to the surface of the spinning rotor. The spinning rotor is separated from the spinning-compartment housing by only a short distance in comparison with the length of the surface of the spinning rotor.
Important advantages of the present invention include a reduced energy consumption because of less air turbulence. Furthermore, less heat is generated in the spinning housing, and the noise level is reduced. Finally, the reduced pressure in the spinning compartment which is a requirement of the spinning process is produced by air friction occuring at the generated surface of the spinning rotor.
The spacing between the spinning rotor and the rotor housing preferably amounts to about 0.5 mm to 3 mm. The spacing is great enough to prevent contact between the spinning rotor and the spinning-compartment housing, but at the same time it is small enough to produce a sufficient stream of air and, accordingly, a sufficiently reduced pressure in the spinning compartment of the spinning rotor.
It is an advantage to provide at the back of the spinning rotor a toroidal intermediate member which is disposed at a slight distance from the spinning rotor. The generated surface of the intermediate member together with the internal contours of the spinning-compartment housing forms a diffusor-like air outlet. This arrangement ensures a uniform stream of air which is essentially free of air turbulence and prevents the stream of air from breaking away. With an appropriate configuration of the side of the toroidal intermediate member which is adjacent to the spinning rotor, a loss-free conversion of the speed of the air into pressure of the stream of air between the spinning-compartment housing and the motor housing will take place. The spinning rotor, the spinning-compartment housing and the intermediate member preferably have corresponding diameters so that they can be readily exchanged for like parts with different masses. As a result, a spinning machine can be equipped with spinning rotors of other sizes without losing the effect of the device according to the present invention.
In order to increase the air-conveying capacity and hence the reduced pressure in the spinning compartment, it is advantageous to provide grooves in the generated surface of the spinning rotor. Furthermore, it is preferable to have the spinning-compartment housing appropriately hingedly connected to the front wall. In this way, rapid access to the spinning rotor is readily available without difficulty.